and so congress in 1996 at that point says, the states are about to experiment with changing this, but the one thing we know is all these federal statutes were passed with the traditional definition in mind. and if rational basis is the test, it has to be rational for congress then to say, well, we are going to reaffirm what this word has always meant for purposes of federal law. >> suppose we look just at the estate tax provision that's at issue in this case, which provides specially favorable treatment to a married couple as opposed to any other individual or economic unit. what was the purpose of that? was the purpose of that really to foster traditional marriage, or was congress just looking for a convenient category to capture households that function as a unified economic unit? >> well, i think for these purposes actually, justice alito, if you go back to the beginning of the estate tax deduction, what congress was trying to do was trying to provide uniform treatment of taxpayers across jurisdictions, and if you look at the brief that senator hatch and some other senators filed,